Centrifugal pulverizer



Dec. 3, 1929. o. A. KREUTZ}BERG 1,737,854

CEN'IRIFUGAL PULVERIZER Filed June 7, 1923 Pafentek] Dec. 3, 1929 PATENTOFFICE OTTO A. KREU'TZBERG, OB LAKE BI'U'IEF, ILLIN'OIS CEN'IBIFU'GALPULVERIZER Applieation am Inne r,

The purpose of this invention is to provide a type of' pulverize'rmdapted tobe built in comparatively small sizes so as to secure to theusers 01 smaller quantities of its product E the same economies whichare now available (0 large manufacturers ano1 producers who can afi"ordto employ the larger types of pulverizing machines. lt consists invarious fea tures and elements of construction and their m combinationas herein shown anl escribed;

and asindicated by che claim.

In the clmwings: Figure 1 is 21 sie e1evation panrfly in seotion showinga pulverizing machine embodying this invenon.

Figute 2 is an ex11 e1evation of the machine with its connoction 't0 theair separator broken away and with a carrier pla'te remove to revealcertain features of construction.

Figure 3 is a large detailed section showing a special form 015 packingring.

Briefly, this machine c01'1sists of an annular grinding member whoseinner 'circumference forms the grinding surface co-operating with a.series of' rollers which are driven around this track.at such a vel0citythat their pressure against itd11e to centrifgal force is several timesgreater than their own weight. The annular member itself is alsorevolved about its axis at a sufficient speed to retain the materialonthe grinding surface untilit is so finely pulverized as to be readilypicked up by the air blast used in conjunction with an air separaterpreferably of a type already shown and described in my pendingapplicmtion Seria1 #47 2,500. By virtue 01T the revolution of therollers their effeotiveness as crushing niembers is multiplied severaltimes and the necessary weight of the machine is thus reduced g reatlyas compared with a mechanism in which on1y the weightof the rollers isutilized. And by virtue of the rotation of the annular grinder andcertain related &eatures hereinafter described, used in conjunction withthe air separ'ator it is p0s- 1923. Serial 11'0. 648,849.

sible to seoure much finer pulverizing than whom gravity alone is reliedupon for feed- 1ng the material.

In the drawings the annular grinding track 1s showr x at 1, s'ecured ina cast rotor, 2, whose hulo, 3, 1s fixed to the end of 2 hollow shaft,4, gournaled in bearings 5, in a, supporting frame 6, within the hollowshaft, 4, there is journalgd a similar shaft 7, carrying a drive pulley,8, at one end shown conncted by a belt, 9, to any convenient souroe ofpower, not shown. At its opposite end thereis secured to said shaft, 7 aspider, 12, an a removable sp1der or plate, 13, which are connected bybo1ts, 15, so as to constitute a cairrier for &sho gmnd1ng rollers, 16,which are shown as four 1n number.

Adjacent the pulley, 8, the shaft, 7, is fitted'with a drive pinion, 17,meshing with s gear, 18, which is fast 011 the hub of a pin- 1on, 19.Said pinion, 19, meshgs with a gear, 20, fixed to the hollow shaft,"' i,for driving tl 1e rotor, 2, at a slower speed than the eat- 11e1 whichsupports the rollers, 16, within 1t and in the same direction ofrotation as sa1d carrier.

For convenience of the ge'ar, 20, may also be arranged to mesh with agear, 21, on a shaft, 22, carrying a sprocket wheel, 23, counected. by achain, 24, with the sprocket, 25, of a feeding device, 26, of familiarconstrum tion in Which a, swinging gate member, 27, is oscillated by apitman, 28, driven from a, crank, 29, on the s'haft of sprocket, 25. F01throwing the feeder out of service when desired, a clutch, 30, may bearranged for disengaging the gear, 25, from its Shaft at Will.

Preferably, although not necessarily, the grinding track or surface ofthe ring, 1, is ooncave in cross section While the peripheral surfacesof the rollers, 16, are corresponding1y convex. Cennecting with theconcave surface of the track, 1, the rotor, 2, provides an annular Wall,31, sloping toward the axis and an ap'plied guardmember, 32, at theolpposite side of the rollers forms a similarly s oping retaining wall,33, so that an annular trough is thus provided in which the materia] tobe pulverized is retained by centrifngal force as rotor, 2, revolves.

The material is fed from the mechanical feeder, 26, into a chute, 34,Which discharges preferablyjust above the edge 0f a central opening inthe plate, 32, to which the intake conduit, 35, of the air separator isconnected. The lower Wall of said conduit is inclined at, 36, so thatmateria l falling from the mouth of the chute, 34, tends to dischargeagainst this inclined surface und to flow or roll into the side 0f theannular trough formed by the Wall, 33, thence by centrifugal force ittends to shift to the center of the trough which is formed by thegrinding ring, 1, entering between the point-s of contact of therollers, 16, and thus cominq directly in their path as they revolve uponthis track.

Bach of the rollers, 16, is formed with a neutral bore, 37, whichprovides considerable clearance around the retaining holt, 15, and eachof said bolts, 15, is specially hardened t0 resist wear und is' furtherprotected by a. 1oose sleeve, 38, which may be of iron pipe or the likeand may be readily replaced when it is worn out by friction between theliore, 37, cf the roller a'nd the holt, 15. In their normal runningposition, the rollers, 16, beil1g held against the grindinsz ring, 1, bycentrifugal force, their bores, 37, d0 not engage either the outer o1the inner sides of the sleeves, 38, but contact with them onlyintesponse to the driving efl'ort of the carrier which serves to revolvethe rollers, 16, within the 'ring, 1. While in a pulverizing mill, it ishardly practicable to lubricate the holt-s, 15, andt-heir sleeves, 38,said sleeves will reduce the friction on the rollers, 16 to the minimum.When either the sleeves, 38, 01' the rollers, 16, become unduly worn,their replacement is rendere very simple by the removal 0f the plate,32, and the spider member. 13, which gives imrnediate access to eherollers on the belts or studs, 15. Similarly. the grinding ring, 1, maybe taken out 0f the rotor, 2, if necessary and refinished orreplaced.

F01 withdrawing the pulverized material from the grinding ring a pulley,8, on the shaft, 7, is connected by a be1t, 10, with a pulley, 11, onthe shaft 0f a suction blower, 40, which is coupled through an exhaustpipe,

y 41, with the air separater, 42, whose interior construction may besubstantially simil'ar to that shown in my pe1iding application, Serial472,500. The air is drawn by the blower, 40, through the air separatorand through the grinding mechanism, entering the latter from a returnpipe, 43, leading from the so-called cyclone of the system to which theblowe'r, 40, discharges through its outlet, 44. The air entering at, 43,asses through openifigs, 45, in the central portion of the' rotor, 2,and the carrier, consisting of the parts 12 and 13, being of spiderformation pen'nits said a.ir t0 be drawn between the grinding ro1lers 16am]. thus in proximity to the material which is being treated on thegrinding ring, 1. That portion 0f this material which is suflicientlyfine is thus picked up by the air current and carried up through theconduit, 35, into the air separator, 42, where the coarser particles aredropped out and returned through the pipe, 46, While the finer materialis -retained in the air dur rent und discharged through the blower 40.

' As shown, the return pipe, 46, from the air separater, 42, dischargiasclose to the inclined lower wall, 36, of the air conduit so that thematerial falling on this inclined surface, 36, will feed down it bygravity under and ast the upwardly moving air current induce by thesuction of the blower, 40. This material to be reground meets thematerial falling from the ahnte, 34, for initial treatment, the passageof the latter material .through the upwardly moving air vcurrent serving1:0 remove therefrom the particles which are a1- ready of requiredfineness. The grinding mechanism is enclosed in a dust-tight casing,

-47 to which the outlet conduit, 35, is closely 'erate without cloudingthe air in its vicinity wi th dust. T0 secure efliciency in the airseparation system, I prefer to form the edge of the annular guard member32, with a groove, 48, interlocking with a groove'd fing, 49, whichdefines the edge of the outlet openingr in the casing 47, so that asubstantially airtight connection is thus afloided between the grindingmember and the casing at this outlet.

F01 excluding dust from the bearings, the hub, 3, of the roter, 2, i smade with an annular re0ess, 2", Which pockets a hardened ring 50,positioned 150 bear against the inner end of the hub, 51, of the carrierand. provided with pressure springs, 52, t0 maintain such engagement.As" shown in Figre 3, the oil duct s 53, leading from the annularchannel, 54, at the end of the bushing, 55, furnish lubricant from theshaft bearing to the recess, 49, which in combination with t he pressurecf the ring, 50, will prevent any d1ist from machingz the bearingitself. A similar ring, 56, is lodged in the end 0f the bearing, 5, tocooperate with the outer shoulder 01 face of the hubs, 3.

I claim:

In a 'pulverizer having rotary crushing elements, a fixed casingtherefor provided with an air inlet opening and a centrally disposedoutlet gpening at one side 0f the plane 01 revolut1on of sa1d elements,means f01 creat ing suction at said outlet opening to carry oif thepulverized material, and an air separater connected by an upwardlydirected passage fr0m said outlet, including an inclined Wall extendingupwardly from the lower side of the outlet to serve as a ahnte forfeeding back coarse material dropping out o:f the air current orreturned by the separaton said separater having a return conduitextending downwardly through said Passage for discharging tovvard theinclined wall.

In testimony whereof, I have hereunto set my band at Chicago, Illinois,this 26th day of February, 1923.

OTTO A. KREUTZBERG.

